Poly (arylene thioether-ketone-ketone) copolymer and production process thereof

ABSTRACT

Disclosed herein is a poly(arylene thioether-ketone-ketone) copolymer comprising (A) at least one poly(arylene thioether-ketone-ketone) segment having predominant recurring units of the formula ##STR1## (B) at least one poly(arylene thioether) segment having predominant recurring units of the formula ##STR2## (a) the ratio of the total amount of the poly(arylene thioether) segment (B) to the total amount of the poly(arylene thioether-ketone-ketone) segment (A) ranging from 0.1 to 9 by weight, (b) the weight-average molecular weight of the poly(arylene thioether) segment (B) being at least 200 but lower than 1000, and (c) said copolymer having a melt viscosity of 2-100,000 poises as measured at 380° C. and a shear rate of 1,200/sec as well as a production process of the poly(arylene thioether-ketone-ketone) copolymer. The copolymer has high crystallinity and heat resistance, uniform composition, and excellent melt stability, processability, handling properties, solvent resistance and moisture absorption resistance.

This application is a division of application Ser. No. 07/686,980 filedApr. 18, 1991, now U.S. Pat. No. 5,250,636.

FIELD OF THE INVENTION

This invention relates to crystalline, heat-resistant poly(arylenethioether-ketone-ketone) copolymers uniform in composition and excellentin melt stability, processability, handling properties, solventresistance and moisture absorption resistance, and more specifically tonovel copolymers containing at least one poly(arylenethioether-ketone-ketone) segment having predominant recurring units ofthe formula ##STR3## at least one poly(arylene thioether) segment havingpredominant recurring units of the formula ##STR4## and also to aprocess for the production thereof.

This invention is also concerned with a process for economicallyproducing such copolymers.

BACKGROUND OF THE INVENTION

In the fields of the electronic and electrical industry and theautomobile, aircraft and space industries, there is a strong demand inrecent years for crystalline thermoplastic resins having high heatresistance of about 300° C. or higher in terms of melting point andmoreover easy melt processability. Polyether ketones having predominantrecurring units of the following structural formula [I]or [II]: ##STR5##were discussed [Polymer, 21, 577 (1980)].

These polyether ketones have excellent heat resistance and mechanicalstrength. However, they use expensive fluorine-containing monomers andutilize, as a solvent, an aromatic sulfone which is costly upon itsseparation and purification from the resulting polymers. The productionprocess thereof thus involves many disadvantages in its industrial use(Japanese Patent Publication No. 22938/1982).

Besides, as poly(arylene thioether-ketone) type polymers, there havebeen proposed polymers having predominant recurring units of thefollowing structural formula [III], [IV], [V]or [VI]: ##STR6##

The poly(arylene thioether-ketone)s (hereinafter abbreviated as "PTKs")having the predominant recurring units of the structural formula[III]have excellent heat resistance, but involve a problem that theyhave poor stability upon melting (Japanese Patent Laid-Open Nos.58435/1985 and 124/1989).

The polymers having the predominant recurring units of the structuralformulae [IV]and [V], respectively, are not suitable for industrialproduction because they must use particular polymerization solvents andmonomers (Japanese Patent Laid-Open Nos. 20017/1986, 197634/1986 and27434/1987).

The poly (arylene thioether-ketone-ketone)s (hereinafter abbreviated as"PTKKs") having the predominant recurring units of the structuralformula [VI]have a melting point as extremely high as about 410° C. Thisis however not all good. Their melt processing temperature are highaccordingly, so that they tend to loss their crystallinity or to undergocrosslinking and/or carbonization, resulting in a rapid increase in meltviscosity, upon their melt processing.

In addition, since PTKKs contain ketone groups in their recurring units,they are poor in solvent resistance and moisture absorption resistance,so that their application fields as heat-resistant resins areunavoidably limited. PTKKs are generally obtained as fine powders. Thishas led to an additional problem upon their production such that theyshow poor handling properties in their collection step afterpolymerization, especially in filtration, washing, drying andtransportation. Still further problems have also arisen such as poormetering property upon melt processing and occurrence of blocking inhoppers or the like.

On the other hand, for example, poly(p-phenylene thioether) as apoly(arylene thioether) (hereinafter abbreviated as "PATE") is used ashigh-performance engineering plastics having excellent heat resistanceand solvent resistance. This polymer is obtained by reactingdichlorobenzene, which is very cheap and industrially available, withsodium sulfide (U.S. Pat. No. 3,919,177). However, its crystallinemelting point is about 285° C. and its glass transition point (Tg) isalso as low as about 85° C. There is thus a demand for development ofpolymers having a higher melting point and a higher Tg.

In order to solve the above problem, there has also been proposedcopolymers in which arylene thioether units and sulfone units of theformula ##STR7## or ketone units of the formula ##STR8## are introducedat random therein (Japanese Patent Publication No. 5100/1984).

It is however impossible to obtain polymers having satisfactoryuniformity in composition, heat resistance and/or melt stability by theprior art process in which a dihalobenzene and a dihalogenated aromaticcompound activated by the ketone group or sulfone group are reactedtogether with an alkali metal sulfide in a polar organic solvent tocopolymerize them, because their reactivity and chemical stability in apolymerization system are different from each other. Namely, theresultant random copolymers tend to have lower crystallinity and poorerheat resistance and mechanical properties as the proportion of thearylene thioether units decreases, in particular, to 90 mole % or less.

It has been proposed to react an aromatic thioether with phosgene or anaromatic dicarboxylic acid dihalide in the presence of a Lewis acid inan aprotic solvent, thereby obtaining polymers having respectivepredominant recurring units of the following structural formulae[VII]and [VIII](Japanese Patent Laid-Open Nos. 104126/1985 and120720/1985): ##STR9## However, the resulting polymers were accompaniedby problems that they have a low degree of polymerization and poor meltstability, and undergo gelation at once.

OBJECTS AND SUMMARY OF THE INVENTION

An object of this invention is to provide copolymers with improvedprocessability, handling properties, solvent resistance and moistureabsorption resistance while retaining the excellent properties, such asheat resistance and crystallinity, of PTKKs as much as possible.

Another object of this invention is to provide a process foreconomically producing such copolymers.

With a view toward improving the processability of a PTKK, the presentinventors first of all attempted to lower the melting point, i.e.,processing temperature of the PTKK by random copolymerization of itsmonomer with monomers of a kind different from the first-mentionedmonomer. Namely, bis(4-chlorobenzoyl)benzene was combined withdihalobenzenes, respectively, followed by random copolymerization.However, the resultant random copolymers tended to have lowercrystallinity and heat resistance and poorer melt stability as theproportions of the dihalobenzenes increased.

Further, bis(halobenzoyl)benzenes have been activated by the ketonegroup and have far higher reactivity compared with dihalobenzenes. Theyhence have extremely poor copolymerizability with dihalobenzenes.

The present inventors then attempted to produce a PTKK-PATE copolymer inwhich a PATE having recurring units of the formula ##STR10## isincorporated as segments in the chain of a PTKK. As a result, it hasbeen found that a copolymer having excellent processability and highcrystallinity can be obtained by using as an oligomer a PATE, which hasa particular average polymerization degree and contains at least oneterminal thiolate group as a reactive terminal group, and reacting thePATE oligomer with a bis(halobenzoyl)benzene under specific conditionsin an organic amide solvent.

It has also been found that a copolymer similar to the above-describedcopolymer can be obtained by reacting the PATE oligomer with a PTKKoligomer under specific conditions.

It has also been revealed that each of these copolymers can be obtainedas granules having good handling properties from its polymerizationsystem by a conventional collection method.

The present invention has been brought to completion on the basis ofthese findings.

According to the present invention, there are thus provided thefollowing copolymer having high heat resistance and crystallinity andproduction processes thereof.

Namely, in an aspect of this invention, there is provided a poly(arylenethioether-ketone-ketone) copolymer comprising (A) at least onepoly(arylene thioether-ketone-ketone) segment having predominantrecurring units of the formula ##STR11## and (B) at least onepoly(arylene thioether) segment having predominant recurring units ofthe formula ##STR12## (a) the ratio of the total amount of thepoly(arylene thioether) segment (B) to the total amount of thepoly(arylene thioether-ketone-ketone) segment (A) ranging from 0.1 to 9by weight,

(b) the weight-average molecular weight of the poly(arylene thioether)segment (B) being at least 200 but lower than 1000, and

(c) said copolymer having a melt viscosity of 2-100,000 poises asmeasured at 380° C. and a shear rate of 1,200/sec.

In another aspect of this invention, there is also provided a processfor the production of a poly(arylene thioether-ketone-ketone) copolymercomprising (A) at least one poly(arylene thioether-ketone-ketone)segment and (B) at least one poly(arylene thioether) segment, whichcomprises at least the following two steps:

i) heating in the presence of water an organic amide solvent containinga dihalogenated aromatic compound, which consists principally of adihalobenzene, and an alkali metal sulfide, whereby a poly(arylenethioether) oligomer having predominant recurring units of the formula##STR13## and at least one terminal thiolate group is synthesized, andii) mixing the oligomer, which has been obtained in the step i), with adihalogenated aromatic compound consisting principally of at least onebis(halobenzoyl)benzene, and optionally, an alkali metal sulfide, anorganic amide solvent and/or water, and heating the resultant mixture toform a poly(arylene thioether-ketone-ketone) segment having predominantrecurring units of the formula ##STR14## thereby forming the copolymer;said first and second steps i) and ii) being conducted under thefollowing conditions (a)-(f):

(a) in the first step i), the ratio of the water content to the amountof the charged organic amide solvent being 0.1-15 (mol/kg), the ratio ofthe amount of the charged dihalogenated aromatic compound to the amountof the charged alkali metal sulfide being 0.3-0.9 (mol/mol), and thepolymerization being conducted in such a manner that the resultingpoly(arylene thioether) oligomer has at least one terminal thiolategroup and its weight-average molecular weight becomes at least 200 butlower than 1000,

(b) in the second step ii), the ratio of the water content to the amountof the charged organic amide solvent being controlled within a range of0.1-15 (mol/kg),

(c) in the second step ii), the ratio of the total amount of the chargeddihalogenated aromatic compound, said total amount being the amount ofthe whole dihalogenated aromatic compounds including the dihalobenzeneand the bis(halobenzoyl)benzene, to the total amount of the chargedalkali metal sulfide, said latter total amount being the total amount ofthe alkali metal sulfide charged in the first step i) and thatoptionally charged in the second step ii), being controlled within arange of 0.95-1.2 (mol/mol).

(d) the ratio of the charged amount of the dihalogenated aromaticcompound consisting principally of the dihalobenzene in the step i) tothe charged amount of the dihalogenated aromatic compound consistingprincipally of the bis(halobenzoyl)benzene in the step ii) beingcontrolled within a range of 0.25-26 (mol/mol),

(e) the reaction of the second step ii) being conducted within atemperature range of 150°-300° C. with the proviso that the reactiontime at 210° C. and higher is not longer than 10 hours, and

(f) in the second step ii), the reaction being conducted until the meltviscosity of the resulting copolymer becomes 2-100,000 poises asmeasured at 380° C. and a shear rate of 1,200/sec.

In a further aspect of this invention, there is also provided a processfor the production of a poly(arylene thioether-ketone-ketone) copolymercomprising (A) at least one poly(arylene thioether-ketone-ketone)segment and (B) at least one poly(arylene thioether) segment, whichcomprises at least the following three steps:

i) heating in the presence of water an organic amide solvent containinga dihalogenated aromatic compound, which consists principally of adihalobenzene, and an alkali metal sulfide, whereby a poly(arylenethioether) oligomer having predominant recurring units of the formula##STR15## and at least one terminal thiolate group is synthesized, ii)heating in the presence of water an organic amide solvent containing adihalogenated aromatic compound, which consists principally of at leastone bis(halobenzoyl)benzene, and an alkali metal sulfide, whereby apoly(arylene thioether-ketone-ketone) oligomer having predominantrecurring units of the formula ##STR16## and terminal halogen atoms issynthesized, and iii) mixing and reacting the poly(arylene thioether)oligomer, which has been obtained in the step i), with poly(arylenethioether-ketone-ketone) oligomer obtained in the step ii) andoptionally, water;

said first through third steps i)-iii) being conducted under thefollowing conditions (a)-(g):

(a) in the first step i), the ratio of the water content to the amountof the charged organic amide solvent being 0.1-15 (mol/kg), the ratio ofthe amount of the charged dihalogenated aromatic compound to the amountof the charged alkali metal sulfide being 0.3-0.9 (mol/mol), and thepolymerization being conducted in such a manner that the weight-averagemolecular weight of the resulting poly(arylene thioether) oligomerhaving at least one terminal thiolate group becomes at least 200 butlower than 1000,

(b) in the second step ii), the ratio of the water content to the amountof the charged organic amide solvent being controlled within a range of0.1-15 (mol/kg) and the reaction being conducted within a temperaturerange of 60°-300° C. with the proviso that the reaction time at 210° C.and higher is not longer than 10 hours,

(c) in the third step iii), the ratio of the water content to the amountof the charged organic amide solvent being 0.1-15 (mol/kg),

(d) in the third step iii), the ratio of the total amount of the chargeddihalogenated aromatic compound, said total amount being the amount ofthe whole dihalogenated aromatic compounds including the dihalobenzeneand the bis(halobenzoyl)benzene, to the total amount of the chargedalkali metal sulfide, said latter total amount being the total amount ofthe alkali metal sulfide charged in the first step i) and that chargedin the second step ii), being controlled within a range of 0.95-1.2(mol/mol).

(e) the ratio of the charged amount of the dihalogenated aromaticcompound consisting principally of the dihalobenzene in the step i) tothe charged amount of the dihalogenated aromatic compound consistingprincipally of the bis(halobenzoyl)benzene in the step ii) beingcontrolled within a range of 0.25-26 (mol/mol),

(f) the reaction of the third step iii) being conducted within atemperature range of 150°-300° C. with the proviso that the reactiontime at 210° C. and higher is not longer than 10 hours, and

(g) in the third step iii), the reaction being conducted until the meltviscosity of the resulting copolymer becomes 2-100,000 poises asmeasured at 380° C. and a shear rate of 1,200/sec.

DETAILED DESCRIPTION OF THE INVENTION

Features of the present invention will hereinafter be described indetail.

Poly(Arylene Thioether-Ketone-ketone) Copolymer

[Chemical structure of copolymer]

The copolymers according to the present invention are copolymerscomprising (A) at least one PTKK segment having predominant recurringunits of the formula ##STR17## and (B) at least one PATE segment havingpredominant recurring units of the formula ##STR18##

The PTKK segment (A) and the PATE segment (B) contain respectively theabove-described recurring units in proportions of at least 50 wt. %,preferably at least 70 wt. %, particularly preferably at least 80 wt. %.

Among these recurring units, the recurring units of the formulae##STR19## are preferred as the recurring unit of the segments (A) and(B), respectively, because they can afford copolymers excellentespecially from the viewpoint of crystallinity, melt stability, heatresistance, mechanical properties, solvent resistance, moistureabsorption resistance and the like.

The copolymer of the present invention can have a desired structurecontaining both segments, such as (A)--(B)--(A)]_(m) (B)--(A), m being 0or an integer of 1 or greater or (A)--(B)--(A)]_(n) (B), n being 0 or aninteger of 1 or greater.

It is however required that the weight ratio of the total amount ofsegments (B) to the total amount of segments (A) be within a range of0.1-9, preferably 0.3-5, more preferably 0.35-4.

The segment (A) serves to impart high degree of heat resistance andcrystallinity to the copolymer. On the other hand, the segment (B)contributes to the reduction of the processing temperature, theimprovement of the solvent resistance and moisture absorption resistanceand the granulation while maintaining the high crystallinity. Therefore,copolymers in which the weight ratio of the total amount of segments (B)to the total amount of segments (A) is at least 0.1 but lower than 1,preferably at least 0.3 but lower than 1 feature particularly good heatresistance and high crystallinity. Ratios in a range of 1-9, preferably1-5 give copolymers excellent especially in processability whileretaining excellent crystallinity. In addition, the resulting copolymersare easy to collect as granules having a suitable particle size, andmoreover become excellent in solvent resistance and moisture absorptionresistance.

However, any weight ratios of the total amount of segments (B) to thetotal amount of segments (A) lower than 0.1 are too low to achieve anysufficient reduction in processing temperature, improvement in solventresistance and moisture absorption resistance or formation intogranules. To the contrary, any ratios higher than 9 lead to asubstantial reduction in heat resistance and disturb the balancingbetween heat resistance and processability. Ratios outside the aboverange are therefore not preferred.

It is essential for the segment (B) to have a weight-average molecularweight not lower than 200 but lower than 1000, preferably, of at least300 but at most 950.

As the length of the segment (B) in the copolymer according to thepresent invention is shorter, the melting point becomes sharper, and theuniformity in composition becomes higher, so that preferredprocessability and physical properties can easily be achieved.

If the weight-average molecular weight of the segment (B) is not lowerthan 1000, the resulting copolymer becomes similar to a block copolymer,so that it has physical properties characteristic of both PTKK and PATE,for example, melting points corresponding to those thereof and requiresa temperature higher than that of the copolymer according to the presentinvention upon its melt processing. Such a high molecular weight istherefore not preferred. Any segments (B) lengthened further are notpreferred because the composition distribution of the resultingcopolymer becomes wider correspondingly. Besides, any segments (B)having a weight-average molecular weight of at most 200 can hardly beproduced.

Incidentally, the weight-average molecular weight of the PATE segment(B) in this invention is determined by gel permeation chromatography(GPC) at a stage of the PATE oligomer.

Measuring conditions are as follows:

Column: SHODEX AT80M/S, two columns in series

Solvent: α-chloronaphthalene

Flow rate: 0.7 ml/min

Temperature: 220° C.

Sample concentration: 0.05 wt. %

Charged amount: 200 μl

Detector: flame ionization detector (FID)

Calibration of molecular weight: standard poly(styrene) and ##STR20##Data processing: SIC 7000B (manufactured by System Instrument Co.)

The segment (A) and segment (B) can contain one or more recurring unitsother than their predominant recurring units of the formulae ##STR21##to an extent that the objects of the present invention are not impaired.

In general, these other recurring units can be introduced into thecopolymers by using the corresponding various dihalogenated aromaticcompounds as comonomers.

[Physical properties of the copolymers]

Physical properties and other characteristics of the copolymersaccording to this invention will next described in detail from theviewpoint of melting point (processability), melt stability,crystallinity and the like.

(1) Melting point (processability):

The melting point of PTKK homopolymer is about 410° C. The extent of areduction in the melting point due to copolymerization with anothermonomer of a different kind, ΔTm=[410° C.-Tm (melting point ofcopolymer)] is generally proportional to the extent of a reduction inthe melt processing temperature. Accordingly, ΔTm can be used as anindex indicative of processing temperature reducing effect, namely,processability improving effect.

ΔTm may preferably be 20°-130° C., more preferably 40°-20° C., mostpreferably 50°-115° C. If ΔTm is lower than 20° C., there is a potentialproblem that the processability improving effect may not be sufficient.If ΔTm is higher than 130° C. on the other hand, there is anotherpotential problem that the copolymer may lose the characteristics as aheat-resistant resin. ΔTm outside the above range is therefore notpreferred.

(2) Crystallinity:

One of great features of the copolymers according to this inventionresides in that they have not only excellent processability but alsohigh crystallinity. Crystallinity imparts high heat resistance to acopolymer. To have a copolymer equipped with high heat resistance, it isessential that the copolymer has sufficient crystallinity.

In general, melt crystallization enthalpy, ΔHmc is proportional to thedegree of crystallization when a molten polymer undergoescrystallization. On the other hand, melt crystallization temperature,Tmc serves as an index of the readiness of crystallization. Therefore,the melt crystallization enthalpy, ΔHmc (400° C.) and meltcrystallization temperature, Tmc (400° C.) of a copolymer according tothis invention as measured when cooled at a rate of 10° C./minimmediately after being heated to 400° C. in an inert gas atmosphere bymeans of a differential scanning calorimeter (hereinafter abbreviated as"DSC") can be used as indices of the crystallinity of the copolymer.

In addition, residual melt crystallization enthalpy, ΔHmc (400° C./10min) and melt crystallization temperature, Tmc (400° C./10 min)measurable upon determination of the residual crystallinity, both ofwhich will be described subsequently, can be used as an index of notonly melt stability but also crystallinity.

The copolymers according to this invention may preferably have ΔHmc(400° C.) of at least 15 J/g, more preferably at least 20 J/g, mostpreferably at least 25 J/g. On the other hand, Tmc (400° C.) maydesirably be at least 180° C., with at least 190° C. being morepreferred. Copolymers having ΔHmc (400° C.) smaller than 15 J/g or Tmc(400° C.) lower than 180° C. may have insufficient heat resistance asheat-resistant polymers and are hence not preferred.

(3) Melt stability:

The greatest feature of the copolymers according to this inventionresides in that they have melt stability sufficient to permit theapplication of conventional melt processing techniques.

Polymers of poor melt stability tend to lose their crystallinity or toundergo crosslinking or carbonization, resulting in a rapid increase inmelt viscosity, upon melt processing.

It is hence possible to obtain an index of the melt processability of apolymer by investigating the residual crystallinity of the polymer afterholding it at an elevated temperature of its melt processing temperatureor higher for a predetermined period of time. The residual crystallinitycan be evaluated quantitatively by measuring the melt crystallizationenthalpy of the polymer by a DSC.

Specifically, it is possible to use as indices of the melt stability ofa copolymer its residual melt crystallization enthalpy, ΔHmc (400° C./10min) and melt crystallization temperature, Tmc (400° C./10 min), whichare determined at a cooling rate of 10° C./min after the copolymer isheld at 50° C. for 5 minutes in an inert gas atmosphere, heated to 400°C. at a rate of 75° C./min and then held for 10 minutes at 400° C. whichis higher than the melt processing temperature of the copolymer.

In the case of a copolymer having poor melt stability, it undergoescrosslinking or the like under the above conditions, namely, when it isheld for 10 minutes at the high temperature of 400° C., whereby thecopolymer loses its crystallinity substantially.

The copolymers of this invention are polymers having the physicalproperties that their residual melt crystallization enthalpies, ΔHmc(400° C./10 min) are at least 10 J/g, more preferably at least 15 J/g,most preferably at least 20 J/g and their melt crystallizationtemperatures, Tmc (400° C./10 min) are at least 170° C., more preferablyat least 180° C., most preferably at least 190° C.

A polymer, whose ΔHmc (400° C./10 min) is smaller than 10 J/g or whoseTmc (400° C./10 min) is lower than 170° C., tends to lose itscrystallinity or to induce a melt viscosity increase upon meltprocessing, so that difficulties are encountered upon application ofconventional melt processing techniques.

Further, the ratio of melt crystallization enthalpy to residual meltcrystallization enthalpy, namely, ΔHmc (400° C.)/ΔHmc (400° C./10 min)can also be used as an index of melt stability. Deterioration by heatbecomes smaller as this ratio decreases. Therefore, it is preferablythat ΔHmc (400° C./10 min) is at least 10 J/g and the above ratio is 5or smaller, more preferably 3 or smaller.

(4) Melt viscosity:

In this invention, the melt viscosity, η* of each copolymer is used asan index of its molecular weight.

Specifically, a polymer sample is filled in a Capirograph manufacturedby Toyo Seiki Seisaku-Sho, Ltd. and equipped with a nozzle having aninner diameter of 1 mmΦ and an L/D ratio of 10/1 and is preheated at380° C. for 5 minutes. Its melt viscosity, η* is measured at a shearrate of 1,200/sec.

The copolymers of the present invention have a melt viscosity, η* of2-100,000 poises, preferably 5-50,000 poises, more preferably 10-30,000poises.

Those having a melt viscosity, η* lower than 2 poises have an unduly lowmolecular weight, so that their flowability is too high to conductconventional melt processing. Even if melt-formed or melt-moldedproducts are obtained, their physical properties are considerablyinferior. Such low melt viscosities are therefore not preferred. On theother hand, those having a melt viscosity, n* higher than 100,000 poiseshave an unduly high molecular weight, so that their flowability is toolow to conduct conventional melt processing. Such high melt viscositiesare therefore not preferred either.

(5) Solvent resistance and moisture absorption resistance:

One of the features of the copolymer according to this invention residesin that PTKK homopolymer has poor solvent resistance and moistureabsorption resistance as one of its disadvantages, whereas thecopolymers of this invention have improved solvent resistance andmoisture absorption resistance.

PTKK homopolymer is easily dissolved in concentrated sulfuric acid atroom temperature and also has high moisture absorption. In general, thecopolymers of this invention are insoluble in concentrated sulfuric acidor require a lot of time for their dissolution in spite of somevariations depending upon their compositional ratios as the weight ratioof the total amount of the PATE segment (B) increases, and moreover,their moisture absorption also becomes lower.

To have a copolymer equipped with preferred solvent resistance andmoisture absorption resistance, it is desirable that the weight ratio ofthe total amount of PATE segments (B) to the total amount of PTKKsegments (A) be preferably at least 0.5, particularly preferably atleast 1.

Production Process of Copolymers

A variety of processes may be contemplated for the production of thecopolymers, for example, including:

(1) A dihalogenated aromatic compound consisting principally of abis(halobenzoyl)benzene is added to and reacted with a PATE oligomerwhich has been prepared in advance, whereby a PTKK segment (A) is formedto form a copolymer.

(2) A dihalogenated aromatic compound consisting principally of adihalobenzene is added to and reacted with a PTKK oligomer which hasbeen prepared in advance, whereby a PATE segment (B) is formed to form acopolymer.

(3) A PTKK oligomer and a PATE oligomer, which have been preparedseparately, are chemically combined together.

The present inventors carefully studied those processes. As a result, ithas been found that the processes (1) and (3) are more suitable forobtaining the copolymers of this invention.

A. Raw materials for copolymers

In the process for the production of a copolymer of this invention, analkali metal sulfide and a dihalogenated aromatic compound are employedas principal raw materials for the polymer and an organic amide solventand water, including water of hydration, as reaction media.

(1) Alkali metal sulfide:

Illustrative examples of the alkali metal sulfide useful in the practiceof this invention include lithium sulfide, sodium sulfide, potassiumsulfide, rubidium sulfide, cesium sulfide and mixtures thereof.

An alkali metal sulfide prepared from an alkali metal hydrogensulfideand an alkali metal hydroxide may also be used.

(2) Dihalogenated aromatic compound:

The dihalogenated aromatic compound employed in the present inventionfor the formation of the PTKK segment (A), including a PTKK oligomer,consists principally of a bis(halobenzoyl)benzene. There is preferablyused 1,4-bis(4-chlorobenzoyl)benzene, 1,4-bis(4-bromobenzoyl) benzene,1,3-bis(4-chlorobenzoyl)benzene, 1,3-bis(4-bromobenzoyl)benzene or amixture of these two or more compounds.

The dihalogenated aromatic compound used in the present invention forthe formation of the PATE segment (B), including a PATE oligomer,consists principally of a dihalobenzene such as p-dihalobenzene orm-dihalobenzene. p-dichlorobenzene and/or m-dichlorobenzene ispreferably used.

As other copolymerizable dihalogenated aromatic compounds, may bementioned, for example, dihalobenzophenones, bis(halobenzoylphenyl)ethers, bis(halobenzoylphenyl) thioethers, dihaloalkylbenzenes,dihalobiphenyls, dihalodiphenyl sulfones, dihalonaphthalenes,bis(halogenated phenyl)methanes, dihalopyridines, dihalothiophenes anddihalobenzonitriles, and mixtures thereof.

As substituent halogen atoms, chlorine or bromine atoms may be usedpreferably from the economical viewpoint. Within a range not giving toomuch effect to cost, a small amount of a fluorine compound may also beused in combination.

It is also permissible to produce a copolymer, which has a partiallycrosslinked and/or branched structure, by causing a trihalogenated orhigher polyhalogenated compound to exist in a reaction system in such asmall amount that the processability and physical properties of thecopolymer may not be impaired to any substantial extent.

(3) Organic amide solvent:

As reaction media useful for the production process of the copolymersaccording to this invention, aprotic polar organic solvents havingexcellent heat stability and alkali resistance can be used. Of these,organic amide solvents, including carbamic amides, and sulfone solventsare particularly preferred.

As such organic amide solvents or sulfone solvents, may be mentionedN-methylpyrrolidone, N-ethylpyrrolidone, N,N'-ethylenedipyrrolidone,pyrrolidones, hexamethylphosphoric triamide, tetramethylurea,dimethylimidazolidinone, dimethylacetamide, ε-caprolactam,N-ethylcaprolactam, sulfolane, diphenyl sulfone, etc. They may also beused as a mixed solvent.

Among these organic amide solvents, N-methylpyrrolidone orN-ethylpyrrolidone and a mixed solvent thereof are particularlypreferred from the viewpoint of the readiness in obtaining a melt-stablecopolymer, thermal and chemical stability, economy, etc.

B. Polymerization process and reaction conditions

For the preparation of the PATE oligomer, for the reaction in which thePTKK segment is formed in the presence of the PATE oligomer to form acopolymer, for the preparation of the PTKK oligomer and for the reactionin which the PTKK oligomer and PATE oligomer are combined together tosynthesize a copolymer, it is necessary to conduct the reaction underspecial conditions, namely by causing water to exist in specific amountsin the reaction systems, controlling the monomer compositions suitably,regulating the polymerization temperatures appropriately, and limitingreaction time at high temperatures to specific short periods of time. Inaddition, it is effective for the production of copolymers having morepreferable physical properties, for example, to choose a suitablematerial for the reactor and to apply stabilization treatment in a finalstage of the reaction.

Unless these reaction conditions are suitably controlled, it isdifficult to provide crystalline copolymers having melt stabilitysuitable for conventional melt processing.

Preparation process of oligomers

(1) PATE oligomer:

The PATE oligomer employed as a raw material for the copolymer of thisinvention and having a specific weight-average molecular weight and atleast one terminal thiolate group can be prepared by having an alkalimetal sulfide and a dihalogenated aromatic compound, which consistsprincipally of a dihalobenzene, undergo a reaction in the presence ofwater in an organic amide solvent under the following conditions(a)-(c):

(a) The ratio of the water content to the amount of the charged organicamide solvent is within a range of 0.1-15 (mol/kg), preferably 0.3-12(mol/kg), more preferably 0.5-11 (mol/kg).

(b) The ratio of the amount of the charged dihalogenated aromaticcompound to the amount of the charged alkali metal sulfide is within arange of 0.3-0.9 (mol/mol), preferably 0.4-0.86 (mol/mol), morepreferably at least 0.5 but less than 0.7 (mol/mol).

(c) The reaction is conducted at a temperature within a range of150°-290° C., preferably 200°-280° C., and controlled in such a mannerthat the weight-average molecular weight of the resulting oligomerbecomes at least 200 but lower than 1000, preferably at least 300 but atmost 950.

In this reaction, the amount of the charged alkali metal sulfide is morethan that of the charged dihalogenated aromatic compound. Therefore, thePATE oligomer formed has at least one terminal thiolate group. Theoligomer having at least one terminal thiolate group means an oligomerhaving a thiolate group on its each terminal or one terminal, or amixture thereof.

The PATE oligomer may contain some crosslinked structure and/or branchedstructure introduced typically by allowing a trihalobenzene or higherpolyhalobenzene to present in a small amount in the polymerizationreaction system.

Incidentally, among the recurring units of the formula ##STR22## therecurring unit of the formula ##STR23## is preferred. (2) PTKK oligomer:

The PTKK oligomer employed as a raw material for the copolymer of thisinvention can be prepared in the following manner.

Namely, the PTKK oligomer can be prepared by having an alkali metalsulfide and a dihalogenated aromatic compound, which consistsprincipally of a bis(halobenzoyl)benzene, undergo a reaction in thepresence of water in an organic amide solvent under the followingconditions (a)-(b):

(a) The ratio of the water content to the amount of the charged organicamide solvent is within a range of 0.1-15 (mol/kg), preferably 1-12(mol/kg), more preferably 2.5-10 (mol/kg). Water contents lower than 0.1mole can hardly provide a PTKK oligomer having high melt stability andmoreover tend to induce decomposition in the polymerization reaction. Onthe other hand, water contents higher than 15 moles result in areduction in the reaction rates. Such high water contents are hence notpreferred economically.

(b) The reaction is conducted at a temperature within a range of60°-300° C. with the proviso that the reaction time at 210° C. andhigher is not longer than 10 hours. The temperature may preferably bewithin a range of 150°-290° C., more preferably 170°-260° C.

The PTKK oligomer may contain some crosslinked structure and/or branchedstructure introduced typically by allowing a trihalobenzophenone orhigher polyhalobenzophenone to present in a small amount in thepolymerization reaction system.

The PTKK oligomer has a reduced viscosity of 0.2 dl/g or lower,preferably 0.1 dl/g or lower, more preferably 0.05 dl/g as determined byviscosity measurement at 30° C. and a polymer concentration of 1.0 g/dlin 98% concentrated sulfuric acid.

The ratio of the amount of the charged dihalogenated aromatic compoundto the amount of the charged alkali metal sulfide upon synthesis of thePTKK oligomer may preferably be at least 1.15 (mol/mol), more preferablyat least 1.2 (mol/mol), most preferably at least 1.3 (mol/mol).

Besides, with respect to the ratio of the amount of the charged organicamide solvent to the amount of the charged alkali metal sulfide in thecomposition of charges upon synthesis of the PTKK oligomer, it isdesirable to charge the organic amide solvent, in general, in an amountof 0.6-100 kg, more preferably 1.0-50 kg per mole of the amount of thecharged alkali metal sulfide.

Production process of copolymers

As the first production process for each copolymer according to thisinvention, may be described the process (Production Process No. 1) inwhich a PATE oligomer is prepared in advance and at least one PTKKsegment is formed in the presence of the PATE oligomer. This process issubstantially a two-step process.

As the second production process for each copolymer according to thisinvention, may be described the process (Production Process No. 2) inwhich PATE and PTKK oligomers are prepared in advance and are thenreacted to combine them together. This process is substantially athree-step process.

The reaction conditions employed in the synthesis stage of the copolymerwill hereinafter be described in further detail.

(1) Water content:

In the process for the preparation of the copolymer of this invention,the water content in the reaction system may desirably be within a rangeof 0.1-15 moles, preferably 2.5-15 moles, more preferably 3.5-14 molesper kg of the amount of the charged organic amide solvent. Watercontents lower than 0.1 mole can hardly provide a copolymer having highmelt stability and moreover tend to induce decomposition in thepolymerization reaction. On the other hand, water contents higher than15 moles result in a reduction in the reaction rates, so that thereaction requires an unduly long period of time. Such high watercontents are hence not preferred in industry. In order to adjust thewater content in a reaction system, the water content may be reduced bydistillation or the like or may be increased by adding water prior tothe initiation of a polymerization reaction.

(2) Composition of monomers charged:

The ratio of the total amount of the dihalogenated aromatic compound tothe total amount of the alkali metal sulfide, both charged uponsynthesis of the copolymer, may desirably be within a range of 0.95-1.2(mol/mol), more preferably 0.97-1.10 (tool/tool), most preferably0.98-1.05 (mol/mol).

Here, the term "the total amount of the charged alkali metal sulfide"means the sum of the amount of the alkali metal sulfide charged uponsynthesis of the PTKK oligomer and/or the PATE oligomer and the amountof the alkali metal sulfide charged upon synthesis of the copolymer.

When a copolymer is synthesized using a portion or portions ofsynthesized PTKK oligomer and/or PATE oligomer, the amounts of thealkali metal sulfide and dihalogenated aromatic compound charged uponsynthesis of each oligomer must be taken into consideration.

Ratios smaller than 0.95 can hardly provide a copolymer having excellentmelt stability and tend to induce decomposition during the reaction. Onthe other hand, ratios greater than 1.2 can only provide a copolymerhaving a low molecular weight. Therefore, such small or large ratios arenot preferred.

Besides, with respect to the ratio of the amount of the charged organicamide solvent to the amount of the charged alkali metal sulfide in thecompositions of charges upon synthesis of the PATE oligomer andcopolymer, it is desirable to charge the organic amide solvent, ingeneral, in an amount of 0.3-5 kg, more preferably 0.4-3 kg per mole ofthe amount of the charged alkali metal sulfide, depending upon thecomposition of the charged dihalogenated aromatic compound.

Where the alkali metal sulfide is lost by a distilling operation or thelike prior to the initiation of the reaction, the term "the amount ofthe charged alkali metal sulfide" as used herein means the remainingamount which is obtained by subtracting the loss from the amountactually charged.

The ratio of the charged amount of the dihalogenated aromatic compoundconsisting principally of the dihalobenzene in the first step to thecharged amount of the dihalogenated aromatic compound consistingprincipally of the bis(halobenzoyl)benzene in the second step must becontrolled within a range of 0.25-26 (mol/mol), preferably 0.9-14(mol/mol), more preferably 1-12 (mol/mol). The bis(halobenzoyl)benzeneserves to impart high degree of heat resistance and crystallinity to thecopolymer. On the other hand, the dihalobenzene contributes to thereduction of the processing temperature, the improvement of the solventresistance and moisture absorption resistance and the granulation whilemaintaining the high crystallinity.

Accordingly, copolymers in which the molar ratio of the charged amountof the dihalogenated aromatic compound consisting principally of thedihalobenzene in the first step to the charged amount of thedihalogenated aromatic compound consisting principally of thebis(halobenzoyl)benzene in the second step is within a range of0.25-2.9, preferably 0.9-2.9 feature particularly good heat resistanceand high crystallinity. On the other hand, ratios in a range of 3-26,preferably 3-14 give copolymers excellent especially in processabilitywhile retaining excellent crystallinity. In addition, the resultingcopolymers are easy to collect as granules having a suitable particlesize, and moreover become excellent in solvent resistance and moistureabsorption resistance.

However, any ratios lower than 0.25 are too low to achieve anysufficient reduction in processing temperature, improvement in solventresistance and moisture absorption resistance or formation intogranules. To the contrary, any ratios higher than 26 lead to asubstantial reduction in heat resistance and disturb the balancingbetween heat resistance and processability. Ratios outside the aboverange are therefore not preferred.

The term "the amount of the charged dihalogenated aromatic compound" asused herein should be interpreted not to include the amount of thehalogen-substituted aromatic compound added in the final stage of thereaction for effecting a stabilizing treatment to be describedsubsequently.

(3) Reaction temperature and reaction time:

In the process of this invention for the production of the copolymer,the reaction is conducted at a temperature in a range of 150°-300° C.,preferably 200°-290° C., more preferably 210°-280° C.

Reaction temperatures lower than 150° C. require an unduly long time toobtain the copolymer and are therefore economically disadvantageous. Onthe other hand, reaction temperatures higher than 300° C. can hardlyobtain the copolymer in a form excellent in melt stability and moreoverinvolve a potential problem of decomposition during the reaction.

The polymerization time required for obtaining a PTKK oligomer orcopolymer of a desired molecular weight becomes shorter as thepolymerization temperature increases but becomes longer as thepolymerization temperature decreases. Accordingly, it is generallyadvantageous to conduct the polymerization at a temperature of 210° C.or higher from the viewpoint of productivity. It is however notpreferred to conduct the reaction at a temperature of 210° C. or higherfor 10 hours or longer, because a PTKK oligomer or copolymer havingexcellent melt stability can hardly be obtained under such conditions.

(4) Reactor:

In the process of this invention for the production of each of the PTKKoligomer, PATE oligomer and copolymer, it is preferable to use, as areactor (including equipment employed for provisional procedures of thepolymerization reaction, for example, those required for dehydration andthe like), a reactor which is made of a corrosion-resistant material atleast at portions with which the reaction mixture is brought into directcontact. The corrosion-resistant material is supposed to be inert sothat it does not react with the reaction mixture.

Preferable examples of such a corrosion-resistant material includetitanium materials such as titanium and titanium-containing alloys andnickel-containing corrosion-resistant materials.

Of these, it is particularly preferred to use a reactor lined with atitanium material.

The use of a reactor made of a corrosion-resistant material such as thatdescribed above makes it possible to obtain a copolymer having high heatresistance and molecular weight.

(5) Treatment in the final stage of the reaction:

Although a copolymer having excellent melt stability can be obtained bythe above-described production process, the copolymer can be obtained ina form improved further in melt stability by adding a certain kind ofhalogen-containing compound to the reaction system and causing it toundergo a reaction in a final stage of the reaction.

As halogen-containing compounds, may be mentioned C₁ -C₃ alkyl halidesand halogen-substituted aromatic compounds. It is particularlypreferable to use at least one halogen-substituted aromatic compoundwhich contains at least one group having electron-withdrawing propertyat least equal to --CO-- group.

As illustrative examples of such a halogen-substituted aromaticcompound, may be mentioned bis(halobenzoyl)benzenes,dihalobenzophenones, dihalodiphenylsulfones, monohalobenzophenones andthe like, and mixtures thereof.

It is desirable to conduct the final-stage treatment by adding theabove-mentioned halogen-substituted aromatic compound in an amount of0.1-20 moles, preferably 0.5-10 moles per 100 moles of the chargedalkali metal sulfide to the polymerization reaction system in the finalstage of the reaction and then allowing it to react at 60°-300° C., morepreferably 150°-290° C., most preferably 220°-280° C. for 0.1-20 hours,more preferably 0.1-8 hours.

(6) Conditions for the granulation:

Another principal feature of the process of this invention for theproduction of the copolymer resides in that the copolymer excellent inmelt stability can be obtained as granules by suitably choosing theaforementioned reaction conditions for the copolymer further. Reactionconditions for obtaining at least 50 wt. % of the resulting copolymer asgranules collectible by means of a screen having an opening size of 75μm (200 mesh) will next be described in further detail. (i) Weight ratioof the total amount of segment or segments (B) to the total amount ofsegment or segments (A) in the copolymer:

The weight proportion of segment or segments (B) in the copolymer is animportant parameter since each segment (B) contributes to thegranulation. When it is desired to obtain the copolymer of thisinvention as granules, it is necessary to control the ratio of the totalamount of segment or segments (B) to the total amount of segment orsegments (A) at 0.3-9, preferably 0.5-6, more preferably 1.0-4, all byweight.

If this ratio is lower than 0.3, it becomes difficult to obtain thecopolymer as granules. On the contrary, ratios higher than 9 lead to asubstantial reduction in the heat resistance of the copolymer. Such lowand high ratios are both not preferred.

(ii) Reaction temperature and time for the granulation:

To obtain the copolymer as granules, it is desirable to raise thereaction temperature to a high temperature of at least 240°-290° C.,more preferably 250°-290° C. in the course of the reaction or in a finalstage of the reaction.

Reaction temperatures lower than 240° C. make it difficult to obtain thecopolymer as granules. On the contrary, it is difficult to obtain thecopolymer in a form excellent in melt stability if the reactiontemperature is higher than 290° C.

The reaction time required for obtaining the copolymer as desiredgranules becomes shorter as the reaction temperature increases.Conversely, it becomes longer as the reaction temperature decreases.Therefore, it is generally advantageous from the viewpoint ofproductivity to conduct the reaction at a high temperature of 250° C. orhigher. It however becomes difficult to obtain the copolymer in a formexcellent in melt stability if the reaction at high temperatures of 250°C. and higher is continued for 7 hours or longer.

C. Collection of copolymers

To collect the copolymer from the reaction mixture, the following methodcan be followed. Namely, after completion of the reaction including thetreatment in the final stage if applied, the reaction mixture issubjected to flushing and/or distillation, whereby the solvent isremoved either partly or wholly to concentrate the reaction mixture. Ifnecessary, the concentrate may be heated to remove any remainingsolvent. The resulting solids or concentrate is washed with water and/oran organic solvent to eliminate soluble components such as salts formedin the reaction. The residue is again dried under heat to collect thepolymer.

By suitably choosing the reaction conditions in the process of thisinvention for the production of the copolymer, at least 50 wt. % of theresulting copolymer can be obtained as granules which can be captured ona screen having an opening size of 75 μm (200 mesh), more preferably 106μm (140 mesh), most preferably 150 μm (100 mesh).

As has been described above, the copolymer can be easily collected asgranules by a screen or the like from the reaction mixture aftercompletion of the reaction. The granular polymer thus collected iswashed with water and/or an organic solvent and then dried under heat toobtain it in a dry form. Since the copolymer is in a granular form andhas excellent handling property, it permits easy separation, waterwashing, transportation, metering and the like.

ADVANTAGES OF THE INVENTION

The present invention can economically provide crystalline copolymersuniform in composition and excellent in heat resistance, melt stability,processability, handling properties and solvent resistance.

The copolymers having high heat resistance and crystallinity accordingto this invention can be used in forming or molding various products.

EMBODIMENTS OF THE INVENTION

The present invention will hereinafter be described in further detail bythe following examples and comparative examples. It should however beborne in mind that the present invention is not limited only to thefollowing examples.

[Example 1] (Production Process No. 1)

(Synthesis of PATE oligomer)

A titanium-lined reactor was charged with 3200 g of hydrated sodiumsulfide (water content: 53.8 wt. %) and 6000 g of N-methylpyrrolidone(hereinafter abbreviated as "NMP"). While gradually heating the contentsto 200° C. in a nitrogen gas atmosphere, 1309 g of water, 1089 g of NMPand 0.39 mole of hydrogen sulfide were distilled out. Thereafter, 104 gof water was added. A liquid mixture consisting of 2320 g ofp-dichlorobenzene (hereinafter abbreviated as "PDCB") and 4380 g of NMPwas then fed, followed by polymerization at 220° C. for 4 hours andfurther at 250° C. for 1.3 hours (PDCB/sodium sulfide=0.85 mol/mol;water content/NMP=3.1 mol/kg), whereby about 13.59 kg of a reactionslurry (Slurry S₁) containing an oligomer (Oligomer P₁) ofpoly(p-phenylene thioether) was obtained.

A portion of Reaction Slurry S₁ was sampled out and then poured intowater to have the oligomer precipitated. The oligomer was collected byfiltration, thoroughly washed in distilled water and then dried underreduced pressure, thereby obtaining an oligomer sample for molecularweight determination. The weight-average molecular weight of Oligomer P₁was 930.

The amount of PDCB (remaining monomer) in the reaction slurry asdetermined by gas chromatography was less than 0.1 wt. % of the chargedamount.

(Synthesis of copolymer)

A titanium-lined reactor was charged with 28.7 g of1,4-bis(4-chlorobenzoyl)benzene (hereinafter abbreviated as "1,4-BCBB"),393 g of Reaction Slurry S₁ thus obtained, 323 g of NMP and 71 g ofwater. After the reactor being purged with nitrogen, the contents wereheated to 265° C. at which they were polymerized for 1 hour.

The reaction conditions upon synthesis of the copolymer were as follows:

(1) The molar ratio of the total amount of the charged dihalogenatedaromatic compound (the sum of the amount of PDCB charged upon synthesisof Oligomer P₁ and the amount of 1,4-BCBB charged upon synthesis of thecopolymer) to the total amount of the charged alkali metal sulfide (theamount of effective sodium sulfide charged upon synthesis of OligomerP₁) was 1.0.

(2) The molar ratio of the amount of PDCB charged in the first step tothe amount of 1,4-BCBB charged in the second step was 5.6.

(3) The ratio of the water content to the organic amide (NMP) was 8.1mol/kg.

(Collection of copolymer)

The resulting reaction mixture in the form of a slurry was passedthrough a screen having an opening size of 150 μm (100 mesh) to collecta granular polymer. The resultant polymer was washed three times withacetone and further three times with water, and then dried at 100° C.for 24 hours, thereby obtaining a copolymer (Copolymer C₁). Thecollection rate of Copolymer C₁ was 72%.

(Properties of Copolymer C₁)

Copolymer C₁ was in the form of granules having an average particle sizeof about 300 μm. This granular form obviated the electrostatic adhesionof the copolymer to a great extent compared to any powdery polymer.

By an infrared (IR) spectrum analysis, a strong absorption peakattributed to ketone group was observed at about 1660 cm⁻¹. Wide angleX-ray diffraction which was conducted using "RAD-B System" manufacturedby Rigaku Denki Kabushiki Kaisha showed a diffraction pattern apparentlydifferent from that corresponding to PATE homopolymer, PTKK homopolymeror a blend thereof, or a block copolymer of PATE and PTKK.

The content of sulfur in Copolymer C₁ was determined by means of asulfur analyzer ("EMIA-510" manufactured by Horiba Ltd.).

The weight fraction W_(b) of the recurring units ##STR24## in thecopolymer can be calculated in accordance with the following equation:

    W.sub.b =[(W-W.sub.1)/(W.sub.2 -W.sub.1)]×100

wherein W means the weight fraction of sulfur in the copolymer, W₁denotes the weight fraction of sulfur in PTKK recurring unit, and W₂represents the weight fraction of sulfur in PATE recurring unit.

By introducing a measured value W=23.0% and calculated values W₁ =10.1%and W₂ =29.6% into the above equation, W_(b) was determined to be 66%.

(Physical properties of copolymer)

The physical properties are collectively given in Table 1.

[Example 2] (Production Process No. 1)

(Synthesis of PATE oligomer)

A titanium-lined reactor was charged with 1000.6 g of hydrated sodiumsulfide (water content: 53.7 wt. %), 6000 g of NMP and 443.2 g of PDCB.The contents were polymerized at 220° C. for 10 hours (PDCB/sodiumsulfide=0.508 mol/mol; water content/NMP=4.98 mol/kg), thereby obtaininga reaction slurry (Slurry S₂).

Further, a portion of Slurry S₂ was treated in the same manner as inExample 1, thereby obtaining an oligomer (Oligomer P₂). The amount ofPDCB (remaining monomer) in the reaction slurry was less than 0.1 wt. %of the charged amount. The weight-average molecular weight of OligomerP₂ was 600.

(Synthesis of copolymer)

A titanium-lined reactor was charged with 682.9 g of the thus-obtainedReaction Slurry S₂ and 98.04 g (0.276 mole) of1,3-bis(4-chlorobenzoyl)benzene (hereinafter abbreviated as "1,3-BCBB").After the reactor being purged with nitrogen, the contents were heatedto 240° C. at which they were reacted for 3 hours.

The reaction conditions upon synthesis of the copolymer were as follows:

(1) The molar ratio of the total amount of the charged dihalogenatedaromatic compound (the sum of the amount of PDCB charged upon synthesisof Oligomer P₂ and the amount of 1,3-BCBB charged upon synthesis of thecopolymer) to the total amount of the charged alkali metal sulfide (theamount of effective sodium sulfide charged upon synthesis of OligomerP₂) was 1.01.

(2) The molar ratio of the amount of PDCB charged in the first step tothe amount of 1,3-BCBB charged in the second step was 1.0.

(3) The ratio of the water content to the organic amide (NMP) was about5 mol/kg.

(Collection of copolymer)

The resulting reaction mixture in the form of a slurry was filtered by afilter paper (class: 5A) to collect solids. The thus-collected solidswere washed with acetone and water repeatedly and then dried at 100° C.,thereby obtaining a copolymer (Copolymer C₂). The collection rate ofCopolymer C₂ was 95%.

(Physical properties of copolymer)

The physical properties of Copolymer C₂ are shown in Table 1. CopolymerC₂ was soluble in concentrated sulfuric acid, and its reduced viscositywas 0.2 dl/g as measured at 30° C. and a polymer concentration of 0.4g/dl in concentrated sulfuric acid.

[Example 3] (Production Process No. 2)

(Synthesis of PATE oligomer)

A reaction slurry (Slurry S₃) containing a PATE oligomer (Oligomer P₃)was prepared in the same manner as in Example 1 except that thepolymerization was conducted by changing the polymerization temperatureand time from 250° C. for 1.3 hours to 240° C. for 3 hours.

The weight-average molecular weight of Oligomer P₃ was 940, and theamount of the remaining PDCB was less than 0.1 wt. %.

(Synthesis of PTKK oligomer)

A titanium-lined reactor was charged with 0.200 mole of 1,4-BCBB, 0.024mole of hydrated sodium sulfide (water content: 53.8 wt. %), 34 g ofwater and 400 g of NMP. After the reactor being purged with nitrogen,the contents were maintained at 200° C. for 10 minutes to react them(water content/NMP=about 5 mol/kg), thereby obtaining a reaction slurry(KS₁) containing a PTKK oligomer (K₁).

A portion of the reaction slurry was poured into water, and the waterwas adjusted to pH 3.0 with hydrochloric acid to have the oligomerprecipitated. The oligomer was collected by filtration, thoroughlywashed with distilled water and then dried at room temperature underreduced pressure in a vacuum drier, thereby obtaining an oligomersample. The thus-obtained oligomer sample was dissolved in 98%concentrated sulfuric acid to give a concentration of 1.0 g/dl so as tomeasure the reduced viscosity of the oligomer at 30° C. The reducedViscosity was as extremely low as 0.05 dl/g.

(Synthesis of copolymer)

A titanium-lined reactor was charged with 429 g of Reaction Slurry S₃containing PATE Oligomer P₃, 255 g of Reaction Slurry KS₁ containingPTKK Oligomer K₁ and 37 g of water. After the reactor being purged withnitrogen, the contents were maintained at 265° C. for 1 hour to reactthem.

The reaction conditions upon synthesis of the copolymer were as follows:

(1) The molar ratio of the total amount of the charged dihalogenatedaromatic compound (the sum of the amount of PDCB charged upon synthesisof Oligomer P₃ and the amount of 1,4-BCBB charged upon synthesis of PTKKOligomer K₁) to the total amount of the charged alkali metal sulfide(the sum of the amount of effective sodium sulfide charged uponsynthesis of Oligomer P₃ and the amount of effective sodium sulfidecharged upon synthesis of PTKK Oligomer K₁) was 1.0.

(2) The molar ratio of the amount of PDCB charged in the first step tothe amount of 1,4-BCBB charged in the second step was 5.

(3) The ratio of the water content to the organic amide (NMP) was 8mol/kg. (Collection of copolymer)

The resulting reaction mixture in the form of a slurry was passed thougha screen having an opening size of 150 μm (100 mesh) to collect agranular polymer. The resultant polymer was washed three times withacetone and further three times with water, and then dried at 100° C.for 24 hours, thereby obtaining a copolymer (Copolymer C₃) as granuleshaving an average particle size of about 200 μm.

(Physical properties of copolymer)

The physical properties of Copolymer C₃ are shown collectively in Table1.

[Comparative Example 1]

(Synthesis of PTKK homopolymer)

A titanium-lined 1-l reactor was charged with 0.073 mole of 1,4-BCBB,0.073 mole of hydrated sodium sulfide (water content: 53.9 wt. %), 500 gof NMP and 38.4 g of water. After the reactor being purged withnitrogen, the resultant mixture was maintained at 260° C. for 2 hours toreact them (water content/NMP=5.0 mol/kg). The reactor was cooled, andthe reaction mixture in the form of a slurry was taken out of thereactor. A portion of the slurry was passed through a screen having anopening size of 75 μm (200 mesh). However, no granular polymer wascollected at all.

The remaining slurry was poured into acetone to have the resultantpolymer precipitated. The polymer was collected by filtration, and thenwashed twice with acetone and additionally twice with water. Acetone andwater were removed to obtain the polymer in a wet form. The wet polymerwas dried at 100° C. to obtain a polymer (R₁) as an ivory powder. Theaverage particle size of Polymer R₁ thus obtained was about 15 μm.Polymer R₁ was soluble in 98% concentrated sulfuric acid but wasinsoluble in e-chloronaphthalene even when holding for 10 minutes at220° C. therein.

[Comparative Example 2]

(Experimental granulation by co- and re-dissolution of homopolymers)

A titanium-lined 1-l reactor was charged with 10 g of fine powdery PTKKPolymer R₁ obtained in Comparative Example 1 and 15 g ofpoly(p-phenylene thioether) ("FORTRON #W214", trade mark product ofKureha Chemical Industry Co., Ltd.) and further with 500 g of NMP and 45g of water. The contents were maintained at 260° C. for 2 hours. Aftercooling, the resultant slurry was passed through a screen having anopening size of 75 μm (200 mesh) to collect a granular polymer. From thefiltrate, a fine powdery polymer was also collected using a filter paper(class: 5A).

The polymers thus collected were separately washed and dried in asimilar manner to Example 1, thereby obtaining 12 g of a granularpolymer (R₂) and a fine powdery polymer.

Like poly(p-phenylene thioether), Polymer R₂ in a granular form wasinsoluble in 98% concentrated sulfuric acid but soluble at 220° C. inα-chloronaphthalene. Its transition points (melting points, glasstransition temperature) were substantially the same as those ofpoly(p-phenylene thioether). It was unable to obtain any copolymer.

This indicates that when PTKK and PATE are only heated together in awater-containing organic solvent, no reaction takes place between bothhomopolymers and hence, any copolymer can not be obtained.

[Comparative Example 3]

(Synthesis of random copolymer)

A titanium-lined 1-l reactor was charged with 0.1212 mole of 1,4-BCBB,0.3576 mole of hydrated sodium sulfide (water content: 53.9 wt. %),0.2365 mole of PDCB, 500 g of NMP and 54.2 g of water. The contents werereacted at 260° C. for 2 hours [water content/NMP=5.0 mol/kg,1,4-BCBB/PDCB=55/45 (weight ratio)].

The reaction mixture in the form of slurry, said mixture containing arandom copolymer (R₃), had a dark brown color and gave off an odor ofdecomposed polymers.

As a result of a gas chromatographic analysis, the remaining monomer wasfounded to be PDCB. Its amount was equal to 22% of the charged amount.The slurry as the reaction mixture was passed through a screen having anopening size of 75 μm (200 mesh). It was however unable to collect anygranular polymer. A fine powdery polymer was recovered from the slurryby using a filter paper (class: 5A) and was then washed and dried in asimilar manner to Comparative Example 1. The melting point of theresulting Random Copolymer R₃ was 157° C. This indicates that 1,4-BCBBand PDCB are substantially different from each other in reactivity andchemical stability in the polymerization system and hence extremely poorin copolymerizability with each other, and moreover, it is only possibleto obtain a copolymer whose melting point is much lower than those ofpoly(p-phenylene thioether) and PTKK homopolymer.

[Comparative Example 4]

(Synthesis of random copolymer)

Polymerization was conducted in a similar manner to Comparative Example3 except that 0.081 mole of 1,4-BCBB and 0.356 mole of PDCB were chargedin lieu of 0.1212 mole of 1,4-BCBB and 0.2365 mole of PDCB [watercontent/NMP=5.0 mol/kg, 1,4-BCBB/PDCB=35/65 (weight ratio)].

The reaction mixture in the form of slurry had a dark red color and gaveoff an offensive odor. The slurry was passed through a screen having anopening size of 75 μm (200 mesh). It was however unable to collect anygranular polymer.

As a result of a gas chromatographic analysis, the remaining monomer wasfounded to be PDCB. Its amount was equal to 14% of the charged amount.As with Comparative Example 3, this indicates that 1,4-BCBB and PDCB aresubstantially different from each other in reactivity and chemicalstability in the polymerization system and hence extremely poor incopolymerizability with each other, so that any satisfactory copolymercan not be obtained therefrom.

[Comparative Example 5]

(Synthesis of PATE oligomer having terminal halogen atoms)

A reaction slurry (S₅) containing a PATE oligomer (P₅) was obtained inthe same manner as in Synthesis of PATE oligomer of Example 1 exceptthat the molar ratio of the amount of the charged PDCB to the amount ofthe charged sodium sulfide was changed to 1.10.

(Synthesis of PTKK oligomer)

A titanium-lined 1-l reactor was charged with 0.0814 mole of 1,4-BCBB,0.126 mole of hydrated sodium sulfide (water content: 53.9 wt. %), 17.8g of water and 325 g of NMP. After the reactor being purged withnitrogen, the resultant mixture was maintained at 220° C. for 1 hour toreact them (water content/NMP=5 mol/kg), thereby obtaining a reactionslurry (KS₅) containing a PTKK oligomer (K₅).

(Experimental synthesis of copolymer)

A polymer (R₅) was synthesized in the same manner as in Example 3 exceptthat the above-prepared slurries containing the respective oligomerswere charged in a titanium-lined 1-l reactor in such a way that theratio of PATE segments to PTKK segments was 70:30 by weight. Theresultant polymer was collected and dried.

Judging from DSC, IR and component analyses, Polymer R₅ wassubstantially identical to poly(p-phenylene thioether).

[Comparative Example 6]

A titanium-lined 1-l reactor was charged with 388 g of Reaction SlurryS₅ prepared in Comparative Example 5 and containing PATE Oligomer P₅,and 0.0814 mole of 1,4-BCBB, 0,126 mole of hydrated sodium sulfide(water content: 53.9 wt. %), 58.1 g of water and 325 g of NMP. After thereactor being purged with nitrogen, the contents were reacted at 260° C.for 2 hours. The resulting polymer (R₆) was collected and dried in asimilar manner to Example 2.

Judging from DSC, IR and component analyses, Polymer R₆ wassubstantially identical to poly(p-phenylene thioether).

The physical properties of the resultant polymer are shown collectivelyin Table 1.

                                      TABLE 1                                     __________________________________________________________________________            PATE recurring                                                                units/PTKK                                                                    recurring units         melt stability                                                                       Melt                                           Charged                                                                            Analyzed    Crystallinity                                                                        (400° C./                                                                     viscosity                                                                          Collection rate                   Poly-   value                                                                              value                                                                              Transition                                                                           (400° C.)                                                                     10 min)                                                                              380° C.                                                                     of polymer (%)                    mer     (weight                                                                            (weight                                                                            points (°C.)                                                                  Tmc                                                                              ΔHmc                                                                        Tmc                                                                              ΔHmc                                                                        1200 sec.sup.-1                                                                    Screen opening                                                                         Collect-                 code    ratio)                                                                             ratio)                                                                             Tg*.sup.1                                                                        Tm*.sup.1                                                                         (°C.)                                                                     (J/g)                                                                             (°C.)                                                                     (J/g)                                                                             (poise)                                                                            150 μm                                                                         75 μm*.sup.2                                                                    ability                                                                           Remark               __________________________________________________________________________    Ex. 1                                                                             C.sub.1                                                                           1.9 (66/34)                                                                        1.9 (66/34)                                                                        109                                                                              311 243                                                                              44  240                                                                              42  100  72  10   Ex- Production                                                                cellent                                                                           process                                                                       No. 1                Ex. 2                                                                             C.sub.2                                                                           0.3 (26/74)                                                                        0.3 (25/75)                                                                        114                                                                              298 211                                                                              48  202                                                                              18   80   0  --   good                                                                              Production*.sup.4                                                             1                                                                             process                                                                       No. 1                Ex. 3                                                                             C.sub.3                                                                           1.7 (63/37)                                                                        1.7 (62/38)                                                                        109                                                                              313 221                                                                              46  208                                                                              29   80  72  8    Ex- Production                                                                cellent                                                                           process                                                                       No. 2                Comp.                                                                             R.sub.1                                                                             0 (0/100)                                                                        PTKK 148                                                                              407 -- --  -- --  --    0  0    Poor                                                                              Fine powder          Ex. 1        homopolymer                                                      Comp.                                                                             R.sub.2                                                                           1.5 (60/40)                                                                        Blend                                                                               86                                                                              285 -- --  -- --  --   48  --   --  PATE alone           Ex. 2                                                    collected as                                                                  granules             Comp.                                                                             R.sub.3                                                                           0.7 (40/60)                                                                        Trial for                                                                          -- 153 -- --  -- --  --    0  0    Poor                                                                              Offensive odor.      Ex. 3        random                                      Poor copoly-                      copolymer                                   merizability         Comp.                                                                             R.sub.4                                                                           1.5 (60/40)                                                                        Trial for                                                                          -- --  -- --  -- --  --    0  0    Poor                                                                              Offensive odor.      Ex. 4        random                                      Poor copoly-                      copolymer                                   merizability         Comp.                                                                             R.sub.5                                                                           2.3 (70/30)                                                                        Trial for                                                                           86                                                                              284 220                                                                              41  205                                                                              31  --   48  --   --  PATE alone           Ex. 5        copolymer                                   collected as                                                                  granules             Comp.                                                                             R.sub.6                                                                           2.3 (70/30)                                                                        Trial for                                                                           86                                                                              281 219                                                                              43  205                                                                              33  --   47  --   --  PATE alone           Ex. 6        copolymer                                   collected as                                                                  granules             Ref.                                                                              *3  (100/0)                                                                            PATE  85                                                                              285 238                                                                              30  218                                                                              25  360  --  --   --                       Ex.          homopolymer                                                      __________________________________________________________________________     Note:                                                                         *1: Determined by DSC at a heating rate of 10° C./min by using a       quenchpressed sheet (pressed at 330-430° C.) as a sample.              *2: Collection rate of each polymer passing through a sieve having an         opening size of 150 μm but recovered on a sieve having an opening size     of 75 μm.                                                                  *3: "FORTRON #W214", trade mark; poly(pphenylene thioether) produced by       Kureha Chemical Industry Co., Ltd.                                            *4: 1,3bis(4-chlorobenzoyl)benzene was used as a monomer                 

Example 4]

(Solubility of polymers in solvent)

Copolymer C₁, PTKK Homopolymer R₁ and poly(p-phenylene thioether)("FORTRON #W214", trade mark; product of Kureha Chemical Industry Co.,Ltd.) were separately hot-pressed and then cooled to form amorphoussheets. The respective amorphous sheets were placed in the solventsshown in Table 2 to investigate their dissolution behavior.

As given in Table 2, the copolymer according to this invention haveproperties different from PTKK homopolymer and PATE homopolymer whichare homopolymers of the components of the copolymer. Namely, thecopolymer is insoluble in both 98% concentrated sulfuric acid, which isa solvent for PTKK homopolymer, and α-chloronaphthalene which is asolvent for PATE homopolymer. In addition, the copolymer is clearlydifferent in dissolution behavior in ap-chlorophenol/1,2,4-trichlorobenzene mixed solvent from both PTKK andPATE homopolymers.

Besides, Copolymer C₁ was insoluble in alcohols, organic amide solvents,ketone solvents and aromatic solvents at room temperature.

                                      TABLE 2                                     __________________________________________________________________________                98% conc.         p-Chlorophenol/1,2,4-trichlorobenzene           Solvent     sulfuric acid                                                                        α-Chloronaphthalene                                                                mixed solvent (50/50 weight                     __________________________________________________________________________                                  ratio)                                          Dissolution temperature                                                                   Room*.sup.1                                                                          Room   220° C.                                                                    Room   215° C.                                                                    215° C.*.sup.2                                                                215° C.*.sup.3                     temperature                                                                          temperature                                                                              temperature                                                                              → room temperature                                                            → 150° C.       Polymer                                                                       Copolymer C.sub.1                                                                         Δ                                                                              X      X   X      ◯                                                                     Precipitated                                                                         ◯                 PTKK Homopolymer                                                                          ◯                                                                        X      X   X      X   --     --                            PATE Homopolymer                                                                          X      X      ◯                                                                     X      ◯                                                                     Precipitated                                                                         Precipitated                  __________________________________________________________________________     X: Insoluble, Δ: Not quite soluble, ◯: Soluble (to          complete clearness to the vision).                                            *.sup.1 State when a solubilizing operation was conducted at room             temperature for 30 minutes.                                                   *.sup.2 State when maintained at room temperature for 2 hours after a         solubilizing operation was conducted at 215° C. for 30 minutes.        *.sup.3 State when maintained at 150° C. for 30 minutes after a        solubilizing operation was conducted at 215° C. for 30 minutes.   

[Example 5] (Production Process No. 1)

(Synthesis of PATE oligomer)

Reaction Slurry S₂ obtained in Example 2 was used.

(Synthesis of copolymer)

A titanium-lined reactor was charged with 682.9 g of Reaction Slurry S₂and 98.0 g of 1,4-BCBB. After the reactor being purged with nitrogen,the contents were heated to 245° C. at which they were reacted for 3hours.

The reaction conditions upon synthesis of a copolymer (C₅) were asfollows:

(1) The molar ratio of the total amount of the charged dihalogenatedaromatic compound to the total amount of the charged alkali metalsulfide was 1.01.

(2) The molar ratio of the amount of the charged PDCB to the amount ofthe charged 1,4-BCBB was 1.0.

(3) The ratio of the water content to the amount of the charged NMP was5 mol/kg. (Collection of copolymer)

Collection was conducted in the same manner as in Example 2, therebyobtaining Copolymer C₅. The collection rate was 95%.

(Physical properties of Copolymer C₅)

Melt viscosity: 140 poises

Melting point: 388° C. (as measured for a quench-pressed sheet)

Melt crystallization temperature: Tmc (400° C.): 334° C. Tmc (400° C./10min): 285° C.

Melt crystallization enthalpy: ΔHmc (400° C.): 54 J/g

Residual melt crystallization enthalpy: ΔHmc (400° C./10 min): 45 J/g

Incidentally, the weight ratio of the sum of PATE recurring units to thesum of PTKK recurring units was 0.3.

Copolymer C₅ was soluble in concentrated sulfuric acid, and its reducedviscosity was 0.33 dl/g as measured at 30° C. and a polymerconcentration of 0.4 g/dl.

[Example 6] (Production Process No. 1)

(Synthesis of PATE oligomer)

A reaction slurry (Slurry S₆) containing Oligomer P₆ of poly(p-phenylenethioether) was obtained in the same manner as in Synthesis of PATEoligomer of Example 1 except that PDCB was charged in such a way thatthe molar ration of the amount of the charged PDCB to the amount of thecharged sodium sulfide was 0.69, and the polymerization was conducted at220° C. for 4 hours and further at 240° C. for 2 hours.

The weight-average molecular weight of Oligomer P₆ was 850 and theamount of PDCB remaining in the reaction slurry was less than 0.1 wt. %of the charged amount.

(Synthesis of copolymer)

A titanium-lined reactor was charged with 700 g of Reaction Slurry S₆thus obtained, 108.7 g of 1,4-BCBB, 592 g of NMP and 128.9 g of water.After the reactor being purged with nitrogen, the contents were heatedto 265° C. at which they were reacted for 1 hour.

The reaction conditions upon synthesis of Copolymer C₆ were as follows:

(1) The molar ratio of the total amount of the charged dihalogenatedaromatic compound to the total amount of the charged alkali metalsulfide was 1.00.

(2) The molar ratio of the amount of the charged PDCB to the amount ofthe charged 1,4-BCBB was 2.2.

(3) The ratio of the water content to the amount of the charged NMP was8 mol/kg.

(Collection of copolymer)

Collection was conducted in the same manner as in Example 2, therebyobtaining Copolymer C₆. The collection rate was 92%.

(Physical properties of Copolymer C₆)

Melt viscosity: 40 poises

Melting point: 364° C. (as measured for a quench-pressed sheet):

Melt crystallization temperature: Tmc (400° C.): 303° C. Tmc (400° C./10min): 257° C.

Melt crystallization enthalpy: ΔHmc (400° C.): 66 J/g

Residual melt crystallization enthalpy: ΔHmc (400° C./10 min): 35 J/g

Incidentally, the weight ratio of the sum of PATE recurring units to thesum of PTKK recurring units was 0.8.

[Example 7] (Production Process No. 1)

(Synthesis of PATE oligomer)

A reaction slurry (Slurry S₇) containing Oligomer P₇ of poly(p-phenylenethioether) was obtained in the same manner as in Synthesis of PATEoligomer of Example 1 except that PDCB was charged in such a way thatthe molar ratio of the amount of the charged PDCB to the amount of thecharged sodium sulfide was 0.80, and the polymerization was conducted at220° C. for 4 hours and further at 240° C. for 2 hours.

The weight-average molecular weight of Oligomer P₇ was 940 and theamount of PDCB remaining in the reaction slurry was less than 0.1 wt. %of the charged amount.

(Synthesis of copolymer)

A charge pot equipped with a heater was mounted on the titanium-linedreactor containing 6300 g of Reaction Slurry S₇. The pot was chargedwith 5211 g of NMP, 617.9 g of 1,4-BCBB and 1135 g of water. After thereactor and charge pot being purged with nitrogen, the respectivecontents were heated to 180° C. and then mixed with each other.

The resultant mixture was heated to 265° C. at which the contents werereacted for 1 hour. After the contents being allowed to cool down to240° C., a final treatment of the reaction was conducted. The finalstabilizing treatment of the reaction was effected by introducing aliquid mixture of 65.5 g of 4,4'-dichlorobenzophenone (hereinafterabbreviated as "DCBP") and 350 g of NMP under pressure and then reactingthe contents at 240° C. for 0.5 hour.

The reaction conditions upon synthesis of Copolymer C₇ were as follows:

(1) The molar ratio of the total amount of the charged dihalogenatedaromatic compound to the total amount of the charged alkali metalsulfide was 1.00.

(2) The molar ratio of the amount of the charged PDCB to the amount ofthe charged 1,4-BCBB was 4.0.

(3) The ratio of the water content to the amount of the charged NMP was8 mol/kg. (Collection of copolymer)

Collection was conducted in the same manner as in Example 1, therebyobtaining Copolymer C₇. The collection rate was 65% when collected bymeans of a screen having an opening size of 150 μm.

(Physical properties of Copolymer C₇)

Melt viscosity: 60 poises

Melting point: 320° C. (as measured for a quench-pressed sheet):

Melt crystallization temperature: Tmc (400° C.): 260° C. Tmc (400° C./10min): 225° C.

Melt crystallization enthalpy: ΔHmc (400° C.): 55 J/g

Residual melt crystallization enthalpy: ΔHmc (400° C./10 min): 40 J/g

Incidentally, the weight ratio of the sum of PATE recurring units to thesum of PTKK recurring units was 1.4.

Example 8] (Production Process No. 2)

(Synthesis of PATE oligomer)

Reaction Slurry S₆ obtained in Example 6 was used.

(Synthesis of PTKK oligomer)

A titanium-lined reactor was charged with 36.3 g of hydrated sodiumsulfide (water content: 53.9 wt. %), 165.6 g of 1,4-BCBB, 700 g of NMPand 43.4 g of water. After the reactor being purged with nitrogen, thecontents were heated to 220° C. at which they were polymerized for 1hour (water content/NMP=5 mol/kg), thereby obtaining a reaction slurry(Slurry KS₈) containing an oligomer (Oligomer K₈) of PTKK.

The reduced viscosity of the PTKK oligomer was determined in the samemanner as in Example 3 and was found to be extremely low and less than0.05 dl/g.

(Synthesis of copolymer)

A titanium-lined reactor was charged with 300 g of Reaction Slurry S₆,472.7 g of Reaction Slurry KS₈ and 37.6 g of water. After the reactorbeing purged with nitrogen, the contents were heated to 265° C. at whichthey were reacted for 1 hour. After the reaction, the contents werecooled down to 240° C., followed by a final treatment of the reaction.The final stabilizing treatment of the reaction was effected byintroducing a liquid mixture of 5.4 g of DCBP and 50 g of NMP underpressure and then reacting the contents at 240° C. for 0.5 hour.

The reaction conditions upon synthesis of Copolymer C₈ were as follows:

(1) The molar ratio of the total amount of the charged dihalogenatedaromatic compound to the total amount of the charged alkali metalsulfide was 0.99.

(2) The molar ratio of the amount of the charged PDCB to the amount ofthe charged 1,4-BCBB was 1.3.

(3) The ratio of the water content to the amount of the charged NMP was8 mol/kg.

(Collection of copolymer)

Collection was conducted in the same manner as in Example 2, therebyobtaining Copolymer C₈. The collection rate was 92%.

(Physical properties of Copolymer C8)

Melt viscosity: 150 poises

Melting point: 382° C. (as measured for a quench-pressed sheet):

Melt crystallization temperature: Tmc (400° C.): 325° C. Tmc (400° C./10min): 281° C.

Melt crystallization enthalpy: ΔHmc (400° C.): 51 J/g

Residual melt crystallization enthalpy: ΔHmc (400° C./10 min): 41 J/g

Incidentally, the weight ratio of the sum of PATE recurring units to thesum of PTKK recurring units was 0.4.

[Example 9](Production Process No. 2)

(Synthesis of PATE oligomer)

A titanium-lined reactor was charged with 2050 g of hydrated sodiumsulfide (water content: 39.1 wt. %), 1952 g of PDCB, 8000 g of NMP and48 g of sodium hydroxide. After the reactor being purged with nitrogen,the contents were heated to react them at 230° C. for 4 hours andfurther at 240° C. for 2 hours (PDCB/sodium sulfide=0.83 mol/mol; watercontent/NMP=5.6 mol/kg), thereby obtaining a reaction slurry (Slurry S₉)containing Oligomer P₉.

The weight-average molecular weight of Oligomer P₉ was 950 and theamount of PDCB remaining in the reaction slurry was less than 0.1 wt. %of the charged amount.

(Synthesis of PTKK oligomer)

A titanium-lined reactor was charged with 76.9 g of hydrated sodiumsulfide (water content: 53.9 wt. %), 690 g of 1,4-BCBB and 7000 g ofNMP. After the reactor being purged with nitrogen, the contents wereheated to 220° C. at which they were polymerized for 1 hour (watercontent/NMP=5.6 mol/kg), thereby obtaining a reaction slurry (SlurryKS₉) containing Oligomer K₉ of PTKK.

The reduced viscosity of the PTKK oligomer was determined in the samemanner as in Example 3 and was found to be extremely low and less than0.05 dl/g.

(Synthesis of copolymer)

A titanium-lined reactor was charged with 360 g of Reaction Slurry S₉and 426 g of Reaction Slurry KS₉. After the reactor being purged withnitrogen, the contents were heated to 265° C. at which they were reactedfor 1 hour. After the reaction, the contents were cooled down to 240°C., followed by a final treatment of the reaction. The final stabilizingtreatment of the reaction was effected by introducing a liquid mixtureof 5.3 g of DCBP and 50 g of NMP under pressure and then reacting thecontents at 240° C. for 0.5 hour.

The reaction conditions upon synthesis of Copolymer C₉ were as follows:

(1) The molar ratio of the total amount of the charged dihalogenatedaromatic compound to the total amount of the charged alkali metalsulfide was 0.99.

(2) The molar ratio of the amount of the charged PDCB to the amount ofthe charged 1,4-BCBB was 4.0.

(3) The ratio of the water content to the amount of the charged NMP was5.6 mol/kg.

(Collection of copolymer)

Collection was conducted in the same manner as in Example 1, therebyobtaining Copolymer C₉. The collection rate was 58% when collected bymeans of a screen having an opening size of 150 μm.

(Physical properties of Copolymer C₉)

Melt viscosity: 40 poises

Melting point: 319° C. (as measured for a quench-pressed sheet):

Melt crystallization temperature: Tmc (400° C.): 318° C. Tmc (400° C./10min): 220° C.

Melt crystallization enthalpy: ΔHmc (400° C.): 47 J/g

Residual melt crystallization enthalpy: ΔHmc (400° C./10 min): 37 J/g

Incidentally, the weight ratio of the sum of PATE recurring units to thesum of PTKK recurring units was 1.4.

[Example 10] (Production Process No. 2)

(Synthesis of PATE oligomer)

Reaction Slurry S₆ obtained in Example 6 was used.

(Synthesis of PTKK oligomer)

A titanium-lined reactor was charged with 98.4 g of hydrated sodiumsulfide (water content: 53.9 wt. %), 355.2 g of 1,3-BCBB, 3000 g of NMPand 217 g of water. After the reactor being purged with nitrogen, thecontents were heated to 220° C. at which they were polymerized for 1hour (water content/NMP=5 mol/kg), thereby obtaining a reaction slurry(Slurry KS₁₀) containing Oligomer K₁₀ of PTKK.

The reduced viscosity of the PTKK oligomer was determined in the samemanner as in Example 3 and was found to be extremely low and less than0.05 dl/g.

(Synthesis of copolymer)

A titanium-lined reactor was charged with 140 g of Reaction Slurry S₆,513.2 g of Reaction Slurry KS₁₀ and 31.4 g of water. After the reactorbeing purged with nitrogen, the contents were heated to 240° C. at whichthey were reacted for 3 hours. Further, a final treatment of thereaction was conducted at 240° C. The final stabilizing treatment of thereaction was effected by introducing a liquid mixture of 2.8 g of DCBPand 50 g of NMP under pressure and then reacting the contents for 0.5hour.

The reaction conditions upon synthesis of Copolymer C₁₀ were as follows:

(1) The molar ratio of the total amount of the charged dihalogenatedaromatic compound to the total amount of the charged alkali metalsulfide was 0.99.

(2) The molar ratio of the amount of the charged PDCB to the amount ofthe charged 1,3-BCBB was 1.0.

(3) The ratio of the water content to the amount of the charged NMP was8.0 mol/kg.

(Collection of copolymer)

Collection was conducted in the same manner as in Example 2, therebyobtaining Copolymer C₁₀. The collection rate was 93%.

(Physical properties of Copolymer C₁₀)

Melt viscosity: 60 poises

Melting point: 296° C. (as measured for a quench-pressed sheet):

Melt crystallization temperature: Tmc (400° C.): 213° C. Tmc (400° C./10min): 205° C.

Melt crystallization enthalpy: ΔHmc (400° C.): 50 J/g

Residual melt crystallization enthalpy: ΔHmc (400° C./10 min): 21 J/g

Incidentally, the weight ratio of the sum of PATE recurring units to thesum of PTKK recurring units was 0.3.

We claim:
 1. A process for the production of a poly(arylenethioether-ketone-ketone) copolymer comprising (A) at least onepoly(arylene thioether-ketone-ketone) segment and (B) at least onepoly(arylene thioether) segment, which comprises at least the followingtwo steps:i) heating in the presence of water an organic amide solventcontaining a dihalogenated aromatic compound, which consists principallyof a dihalobenzene, and an alkali metal sulfide, whereby a poly(arylenethioether) oligomer having predominant recurring units of the formula##STR25## and at least one terminal thiolate group is synthesized, andii) mixing the oligomer, which has been obtained in the step i), with adihalogenated aromatic compound consisting principally of at least onebis(halobenzoyl)benzene, and optionally, an alkali metal sulfide, anorganic amide solvent and/or water, and heating the resultant mixture toform a poly(arylene thioether-ketone-ketone) segment having predominantrecurring units of the formula ##STR26## thereby forming the copolymer;said first and second steps i) and ii) being conducted under thefollowing conditions (a)-(f): (a) in the first step i), the ratio of thewater content to the amount of the charged organic amide solvent being0.1-15 (mol/kg), the ratio of the amount of the charged dihalogenatedaromatic compound to the amount of the charged alkali metal sulfidebeing 0.3-0.9 (mol/mol), and the polymerization being conducted in sucha manner that the resulting poly(arylene thioether) oligomer has atleast one terminal thiolate group and its weight-average molecularweight becomes at least 200 but lower than 1000, (b) in the second stepii), the ratio of the water content to the amount of the charged organicamide solvent being controlled within a range of 0.1-15 (mol/kg), (c) inthe second step ii), the ratio of the total amount of the chargeddihalogenated aromatic compound, said total amount being the amount ofthe whole dihalogenated aromatic compounds including the dihalobenzeneand the bis(halobenzoyl)benzene, to the total amount of the chargedalkali metal sulfide, said latter total amount being the total amount ofthe alkali metal sulfide charged in the first step i) and thatoptionally charged in the second step ii), being controlled within arange of 0.95-1.2 (mol/mol) (d) the ratio of the charged amount of thedihalogenated aromatic compound consisting principally of thedihalobenzene in the step i) to the charged amount of the dihalogenatedaromatic compound consisting principally of the bis(halobenzoyl)benzenein the step ii) being controlled within a range of 0.25-26 (mol/mol),(e) the reaction of the second step ii) being conducted within atemperature range of 150°-300° C. with the proviso that the reactiontime at 210° C. and higher is not longer than 10 hours, and (f) in thesecond step ii), the reaction being conducted until the melt viscosityof the resulting copolymer becomes 2-100,000 poises as measured at 380°C. and a shear rate of 1,200/sec.
 2. The process as claimed in claim 1,wherein the segment (A) has predominant recurring units of the formula##STR27## and the segment (B) has predominant recurring units of theformula ##STR28##
 3. The process as claimed in claim 1, wherein thesegment (A) has predominant recurring units of the formula ##STR29## andthe segment (B) has predominant recurring units of the formula ##STR30##4. The process as claimed in claim 1, wherein in each of the steps i)and ii), the reaction is conducted in a reactor at least a portion ofwhich, said portion being brought into contact with the reactionmixture, is made of a corrosion-resistant material.
 5. The process asclaimed in claim 4, wherein the corrosion-resistant material is atitanium material.
 6. The process as claimed in claim 1, wherein theorganic amide solvent is at least one pyrrolidone selected fromN-methylpyrrolidone and N-ethylpyrrolidone.
 7. The process as claimed inclaim 7, wherein at least 50 wt. % of the resulting copolymer is in theform of granules recoverable on a sieve having an opening size of 75 μm.